Freeness indicator and recorder



June 2, 1936.

(a s. WITHAM, JR

FREENESS INDICATOR AND RECORDER Original Filed June 28, 1952 5 Sheets-Sheet 1 INVENTUR: GEUREE '5.W1THAM JR..,

H15 ATTEJRNEYE June 2, 1936.

s. s. WITHAM, JR

FREE-HESS INDICATOR AND RECORDER 3 SheetS-Sheet 2 Original Filed June 28, 1952 INVENTEIR; GEDHEEI .5. WITHAIVL H15 AT: DRNEY'E June 2, 1936. G. s. WITHAM, JR 19,997

FREENESS INDICATOR ANDBECORDER Original Filed June 28, 1932 5 Sheets-Sheet 3 INVENTDRI Ea BREE 5. WITHAr-IJR,

H15 ATTuENEya Retained June 2,1936 7 UNITED STATES Original No. 1,945,908,

Serial No. for reissue August ticlalms- One of the dimcult problems in the manufacture of paper, which is a' more or less continu ous operation, is toproth'ice a. product having unitorm characteristics throughout such as Mullentear, opaqueness, texture. bulk, etc. Likewise, the making of a to a definite specification or in which the characteristics of a given samplewill be duplicated presents considerable dlillculty. Paper is made from fluent materials and the characteristics oi these materials determine the characteristics of the finished paper.

In my copending application Ser. No. 537 ,342 I have disclosed methods and apparatus for determining, recording and controlling the density, consistency or specific gravity of fluent paper stock. While a means for maintaining a uniform consistency of the fiuent. materials is a very im portant factor-in producing paper'to a definite specification, it is recognized that stock of uni- 2 form freeness is also necessary to produceconsistently a unii'orm product.

If there ls.very much coarse fiber and insufllcient filler (fine, fiuiIy fiber) in the stock, the

texture, and the water will pass through quickly. Such a stock is called free stoc 0n theother hand, it there is a. large amount of fiber mixed with fiber having frayed out ends, a denser mat will be made. The water will then pass through so the mat more slowly and the mixture will be known as slow stock. The rate of drainage of water through the fiber mat is a valuable indication of the quality of the pulp mixture, and the uniformity; strength and finish of the paper are 86 largely dependent thereon.

The freeness oi the stock also afiords an indication of the character of the treatment that the stock has received in the heater and particularly duri the initial treatment therein. If, for example, the roll be put down sharply on the plate at the beginning of the operation, the

fibers may retalntheir length but they will be considerably weakened and the paper will have a raw, soft finish which is due to the overfree 46' stock or stuii. On the other hand where a large proportion of ground wood is incorporated in the stock; the fibers of which reduce very quickly in the beater, the stockv soon arrives at the state knownas slow stufi" which results in a poor 60 quality or paper and seriously cuts down the production of the paper machine.

I The primary object of my invention is to provide a means which .will continuously indicate the freeness of paper stock undergoing preparalt tion. Since the "indica ireeness of any stock 1am magmas mores-roe m ancosns'n GeorgmSQWitham, In, uimin. u. a.

819,729, June 28, 1932.

24, 1934, Serial No.

fi'oer mat will not-pack well, it will be of open PATENT OFFICE dated February 6, 1934, Application 141,845

varies with its density and temperature, another object 01' my invention is to provide an appropriate means for regulating or automatically controlling the density and temperature of the stock whereby is obviated the necessity of correcting the ireeness indicated for temperature and density.

My invention, therefore, includes the method 'of procedure and the novel elementsucombinations and arrangements thereof described below and illustrated in the accompanying drawings in which Fig. 1 is a general elevation view, partially in section, showing the application of my device to a jordan; I

Fig. 2 is an elevation view, partially in section, showing details of apparatus used in con nection with my device; Fig. 3 is an elevation view, partially in section, of a modified form of rotating element which I may employ in determining the freeness of the stock; g

Fig. 4 is a side elevational view, partially in section, of Fig. 3;

Fig. 5 is a. side elevation similar to Fig. 1 but showing a modified form of apparatus;

Fig. 6 is a plan view of Fig. 5;

Fig. 7 is an elevation view showing the application of my freeness indicator to a pulp grinder;

Fig. 8 is an end-elevation view, partially in section of a beater, in the plane 88 of Fig. 10 showing how an ordinary washer may be utilized in determining the freeness of the stock;

Fig. 9 is a .plan view of Fig. 8, and

Fig. 10 is a side elevation view of Figs-8 and 9.- Referring particularly to Figs. 1, 2, 3, and 4 of 4 the drawings which show the general assembly with details of onemodification or my invention as applied to a Jordan, I represents the Jordan which is supplied with material from the head box 2 through the pipe While ahead box is not absolutely 'neeessaryit is highly desirable in asmuch as it maintains a uniform head of material on the jordan. The treated material delivered irom the jordan flows through the pipe 4 into the tank or vat 5. This vat is provided with a channel 5 which may be about the width shown in Figs. 2 and 3. Only a portionof the material delivered from. the jordan is diverted through the channel 6 and the volume delivered is controlled by means of gate valves 1 and 8 which are separably. operable through the hand wheels 9 and l0 respectively. The gate valve 1 controls the flow from the iordan into the vat 5 while the valve 8 controls the outflow of material from W I the vat. It is obvious that by adjusting the relative sizes of the openings through the valves 1' and 3 that the depth or-volume of the material diverted through the channel 8 may be varied and maintained at will. To prevent any direct flow from the Jordan through the diversion chanjnel, a bailie il may be provided in front of the opening from the Jordan. Since, as will appear later, it is necessary that the rotating element I2 have its lower peripherysubmerged in the stock flowing through the diversion. channel, thischarmel is provided at its lower end with a dam I 3 over which the diverted material flows a water wheel. That to jointhe main body of through the discharge l4.

The rotating'element I2 is quite similar to the rotating element disclosed in my copending application Ser. No. 537,342 for controlling the consistency of the stock in that it is provided about its periphery with paddles or blades l5 which cause it to function very much like an under shot is to say, the stock flowing through the diversion channel 6 causes the wheel 12' to rotate.

Since the rate of flow of stock through the diversion channel depends upon the consistency of the stock, it is quite evident that the rate of rotation of the wheel will be inversely proportional to the consistency. In other words, when the consistency is high the flow of stock through the diversion channel is slow and the wheel i2 rotates slowly. When the density or consistency is low, the. volume of stock flowing through the channel is increased, it flows faster under the same head and thereby drives the wheel l2 at a higher rate of speed of rotation of the wheel I2 is utilized to control the consistency either by means of the apparatus shown in my copending application or by that which will now be described.

Secured to the shaft l6 upon which the rotating element I2 is mounted is a sprocket wheel l1 driving a smaller sprocket i8 through chain I 9. The sprocket 20 which drivesa sprocket 2i associated with a speed increasing or tenup gear device 22. This device, by means of the belt. 23 turns the shaft 24 of a tachometer 25. The tachometer is material passing out preferably of the recording type and providedwith a clock driven dial 26 calibrated in consistencies and'upon which the consistency is recorded.

Connected with a stylus 21 by means of a link mechanism 28 is a mercury switch 28, which may be of the type commercially knownas a Mercoid switch. In the position shown in the drawings, the mercury is in the lower end of the tube 30 and is "ad contact". When the stylus moves in toward the center of the chart 26, which occurs when the. consistency increases andthe'speed of the tachometer is therefore reduced, the mercury switch is tilted by means of the link mechanism 28, and the wires 3| and 32 are electrically connected to form a circuit through the busses 33 and the solenoid switch 34 which actuates a valve 35 to admit diluent through the pipe 36. A second mercury switch 30' may be usedto light a telltale lamp I30; thus providing a visible indication that valve 35 is open.

The lever 31 of the link mechanism 28 may be adjustably secured to the shaft 38 of the stylus 21 so that the mercury switch may be tilted to actuate the diluent valve at any position of the stylus. By this means the consistency of the, material is maintained substantially constant.

Since the "indicated? freeness of the air pressure on the valve.

of speed. This variation in the rate sprocket iBls secured'to the same shaft as chamber 50 produce a rate of outflow equal to it is extremely deprovided for maintaining the temperature of the material substan tially constant. This result is attained by means of the followingmechanism. 39 is the heat sensitive element of a thcrmometric device and is immersed in the stock near the diversion channel. This heat sensitive device is associated with a single type regulator 40 which serves to admit air to the pipe 4| for actuating valve 42. This valve 42 is in a steam line 43 and when actuated admits steam to the stock flowing into the jordan. The gauge 44 shows the air pressure available for actuating the valve 42 and the gauge 45 shows the Regulators of this type are manufactured by a number of companies and are quite well known. The hand 40 of the regulator may be set manually so that the steam valve can be actuated to maintain any desirable temperature. V

So far I have described only those devices which maintain the consistency and temperature substantially constant and eliminate the necessity of making corrections for these two factors, in so far as the indicated freeness is concerned.

Referring now more particularly to Fig. 2, 3, and 4, I" will explain in detail the method and apparatus for determining, indicating and recording the freeness of the stock. The rotating element l2, in addition to having paddles l5 about its periphery, is also provided with a plurality of equally spaced screened openings 46. When the lower periphery of the element I2 is submerged in the stock flowing through the diversion channel, these screens will also be submerged and the more fluent material in the stock will pass therethrough. Since the element I2 is rotating at a substantially uniform rate of.speed (except for accelerations and decelerations due to variations in consistency), the volume of water which flows *siphon is primed or actuated by permitting water to flow downwardly'through the pipe 49 which withdraws air from the chamber 50 thereby causing the liquid which flows through the screen to flow upwardly in pipe 41 and downwardly through and pipe 5i into the graduated element 43. This element is preferably made with an upper section 52 and a lower section 53 which are connected together by coupling 54 provided with an annular recess 55 therein opening into the lower section 53. The liquid flowing into the tubular element 48 gradually rises until it reaches the level of the outflow pipe 56 through which itis discharged. The rate of discharge through this-pipe can be regulated by means of a valve 51 provided with a dial 58 and hand 59 indicating the extent of the opening thereof. Assuming that the liquid is flowing downwardly .through the pipe 5| into the tubular element 48 at a uniform rate, as would be the case with uniform freeness, the valve 51 may be so regulated that the height of the liquid in the upper section 52 can be maintained at any desired level. If the freeness of the stock increases, liquid will flow at a faster rate into the tubular element 43 and the level of liquid therein will rise until the head is suflicient to the inflow.

reverse will occur. By graduating the upper portion of the tubular element It and calibrating oi the material going through. I The tubular element 48 and the associated parts. thus constitute a' device in which liquid flowing through the filter element accumulates and for indicating variation in the rate of flow of liquid through said element from the normal rate of flow therethroughoi liquid from standard stock.

As the liquid rises in the tubular element and passes above the coupling ll, it willbe apparent that air will be compressed oi the annular recess 55 and that the extent of this compression will depend upon the height or liquid in the upper portion 52 of the tubular element. The degree of compression indicates the level 01 liquid in the tubular element, and since this level varies with the i'reeness, the i'reeness may be indicated by means of a recording level gauge 60 calibrated to ireeness and connecting with the annular recess 55 through the pipe ii. The lower portion 53 of the tubular element provides a sump into which will settle heavier particles in the stock. By graduating this portion so that the depth of sedia fair indication of the amount of filler etc. passing through the wire will be obtained. v

In order that the screens may be freed of any mat or fiber accumulating thereon, I provide an air or a steam pipe 52 having its discharge of the screen openings'at some point of their travel above the surface the liquid in the diversion channel.

In Figs. 3 and 4 I have shown a modified form oi freeness tester which operates upon a principle quite similar to that employed in the ordinary washer. Instead of withdrawing the liquid which flows through the screens by means of a siphon, the interior of the rotating element is divided into as many separate pockets or compartments 63 as, there are screened openings and each one of these compartments is through which the liquid flows from the compartments by gravity into the enlarged axial pipe 65 and from which it may be discharged into a tubular receptacle similar to that shown at 48.

In Figs. 5 and 6 I have shown a slight modification of my ireeness indicator in which the rotating element 66, provided with screened peripheral openings therein, is driven. by means of a motor 61 through an appropriate reduction gearing 68 by mean'sof the chain 69. The interior of the element 66 may be provided with a plurality of separate pockets or compartments, one for each screen, with pipes discharging into element Ii. from the element Ii may be regulated by' means of a valve 13 provided with a hand 13 and a graduated dial 14 indicating the degree of opening thereof. By properly adjusting the valve sistency may be maintained substantially constant in the element Ii, and by graduating this tube and calibrating the same in known ireeness, it is possible to read therefrom at any time the freeness oi the material. As in the device provided with an approximately radial discharge pipe Bi V 19.091 when the ireeness or the met decreases the these graduations'with known ireeness, it is possible to read therefrom at any time the Ireeness I in the upper portion in nozzle 62 disposed adjacent the inner side the central hollow shait Ill and from which thematerial is delivered into the vertical 'tubular- The rate of flow of the material opening, the height of material for a given con- Pig. 2, a recording level gauge Wacthe pressure oithe material in the eleshown in' tuatedlw ment Ii may be'employed to make a record oi variations in the level of material and hence a record of it's ireeness. v

In Figs. 5 and 6, parts which are similar to thoseparts described in'l 'lgs. land 2 are indicated by the same numbers in Figs. 1 and 2 plus 100. That is to say, t Fig.1isindicatedas llandlnFifl-Sandfiit is-iil. -.It is to be understood that the device shown in Figs. 5 and Gshould be used in con-' nection with some means for maintaining the density or consistency and the temperature of the material substantially constant; otherwise, it will be necessary to correct the indicated iree- .ness tor these two factors.

In Fig. 7, I have shown the application of my treeness device to a .pulp grin'der. The pulp grinder is represented generall'yby l0 and the water is supplied thereto through The ground pulp fiows over the weir or dam I! the height of which may be adjusted by means of a hand wheel 1!. Rotatably mounted with its lower periphery submerged in the stream flowdischarge pipe inthe pipe 11.:

in all respects similar to the element l2 shown in Figs. 1 and 2. This element drives the recording tachometer 2! provided with an electric menttherein can be measured from time to time switch in all respects similar to that described in connection with Fig. l and which controls a valve admitting water to the grinder. The

liquid passing through the screened apertures oi the element. i2 'is withdrawn by means of the siphon apparatus, represented generally by 83 and is delivered into the receptacle 8i. It is understood, 0! course, that a rotating element I! may be substituted for element ii.

The rate of flow oi the material out of the receptacle 8i can be regulated by means-oi a valve 82 provided with a dial 83 and a hand 84 indl-' eating the extent of the opening of the valve.

Variations in the height of the material in the receptacle 8| and hence the freeness. thereof may be recorded by the recording level gauge 85.-

Variations in the rate 01! speed at which the element i2 is driven by the outflowing stream of material eiIect corresponding variations in In Figs. 8, 9, and 10 I have shown the use of v an ordinary washer in connection with a beating engine for determining the freeness of the material. In these figures 95 represents the beater tub and I6 is the washer. The volume of material flowing through the washer screens 81 is proportional to the freeness of the stock and this liquid is delivered into the receptacle 8!. The outflow of' maternal from the receptacle 88 is controlled by means of a valve 88 provided with a dial 9' indicating the extent of the opening thereof and permitting settings to various degrees oi openings. a transparent gauge 9i, similar to a water gauge. may be associated with the receptacle Cl and which will provide an indication oi the depth of thematerial therein. This gauge may, of course, be graduated in freeness and the freeness at any time read directly therefrom. A recording level gauge 92 may also be employed in connection with the receptacle stood that the drawings are merely illustrative and that changes within the purview of the appended claims may be made without departing from the true scope and spirit 01' my invention in its broader aspects.

What I claim is:

1. In a device 01' the character described, a drum having a ioraminous periphery mounted to rotate in a vertical plane with its lower portion submerged in a flowing body of paper stock and provided with means adapting it to be driven by said stock as an undershot wheel; means responsive to variations in the rotative speed of said drum for regulating the consistency of the stock; and means for determining variations in the rate of flow of said liquid through the foramina in said drum.

2. In a device of the character described,'a drum mounted to rotate with its lower periphery submerged in a flowing body of paper stock and provided with means adapting it to be driven by said stock as an undershot wheel; the periphery of said drum being divided into a plurality of separate compartments having screened openings communicating with the stock in said stream;

means responsive to variations in the rotative speed of said drum for regulating the consistency of the stock; and means for determining variations in the rate oi. flow of said liquid into said compartments.

3. In a stock treating system of the character described, a ioraminous element both sides of which are normally exposed to atmospheric pres sure, means for exposing one-side of said element to liquid pressure from said stock, and means continuously responsive to slight'variations in the rate of flow of liquid through said element for indicating the current rate of flow therethrough.

4. A device for determining the rate of flow of water through a mat of paper stock which comprises an element having a screened opening therein, means for successively submerging the screened portion of said element in a body of said stock and withdrawing it therefrom while maintaining balanced atmospheric pressures on both sides 01 said screened opening whereby, when submerged, a filter mat of said stock will be temporarily formed over said screened opening and control the rate of flow of liquid therethrough, means for withdrawing and segregating liquid flowing through said opening during the periods of submergenceand means responsive to slight variations in the volume of liquid segregated during such successive periods of submergence for indicating the current rate of flow oi liquid through said opening.

5. The method of determining the current freeness of paper stock undergoing preparation which comprises maintaining said stock at substantially uniform consistency, repeatedly establishing and momentarily maintaining filter mats of material from said stock, creating a flow of liquid from said stockvthrough said mats while maintaining balanced atmospheric pressures on opposite sides thereof, segregating the liquid flowing through said mats in a suitable receptacle, and withdrawing liquid from said receptacle at a rate calculated to maintain the surface of the liquid therein at a fixed level intermediate the top and bottom of said receptacle when the freeness of said stock corresponds to a desired standard; whereby variations in the level of the liquid in said receptacle will indicate variations in the freeness of said stock, and the current level will indicate the current freeness.

.6. The method of determining the current freeness of paper stock undergoing preparation which comprises maintaining said stock at substantially uniform temperature and consistency, repeated ly establishing and momentarily maintaining filter mats of material from said stock, creating a flow of liquid from said stock through said mats while maintaining balanced atmospheric pressures on opposite sides thereof, segregating the liquid flowing through said mats in a suitable receptacle, and withdrawing liquid from said receptacle at a rate calculated to maintain the surface of the liquid therein at afixed level intermediate the top and bottom ofv said receptacle when the freeness of said stock corresponds to a desired standard; whereby variations in the level of the liquid in said receptacle will indicate variations in the freeness of said stock, and the current level will indicate the current freeness.

GEORGE S. WITHAM, JR. 

